Infusion syringe

ABSTRACT

A device for applying and measuring fluid pressure in the lumen of a syringe in communication with a tubular member attached to a needle inserted into the body of a disk found in the spinal column of the back. A pressure transducer is integrally mounted in the plunger of the syringe under the plunger tip, such that the force applied by the plunger to the fluid in the syringe is transmitted to the transducer and the resulting electronic signal is converted to a display value aiding the physician in diagnosing diseased disks in the back. Other uses of pressure applying monitoring syringes for other applications in communication with the body also benefit from the disclosed syringe construction, such as percutaneous translumenal angioplasty (PTA) procedures.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication 60/468,398, filed May 5, 2003, the contents of the entiretyof which are incorporated by this reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to an infusion syringe apparatus forapplying and monitoring fluid pressure applied to the intervertebraldisk of the spinal column, or more specifically, monitoring of thepressure applied through a needle or cannula through the annulusfibrosus of the disk and into the nucleus pulposus thus allowing thediagnosis of diseased or ruptured disks. The field may further includefluid pressure-inducing syringes and methods involved in percutaneoustranslumental angioplasty (PTA) procedures.

[0004] 2. State of the Art

[0005] Infusers utilized in diskography and balloon angioplasty are wellknown and established in medical practice. The tools typically appliedto angioplasty have found application in other fields as well, such asopening diseased carotid arteries and improving or reestablishing bloodflow to the extremities of diabetics and similar purposes. Similar toolshave been used in the field of pain diagnosis and management related toorthopedic procedures related to the spine.

[0006] The number of failed or ineffectual spine surgeries has driventhe development of new techniques for verifying the location of damageor injury in the vertebral column. Typically these procedures involvethe insertion of a curved or specifically shaped cannula or needle underthe transverse process of the vertebra and around the inferior articularprocess and penetrate the annulus fibrosus. Application of fluidpressure to the nucleus pulposus will either go undetected, createrelief from chronic pain or induce a pain episode due to the pinching ofa nerve. By the application of this technique to suspect vertebral disksa physician can identify the pain locus and thus use the appropriateintervention to provide relief for the patient. This process istypically performed utilizing ionic contrast media, typically made fromionically bound iodine. This media allows the physician to view theprocedure on a fluoroscope which aids in needle positioning and visualdiagnosis. Diagnosis is based on the inter-vertebral disks' ability, orinability, to contain the contrast media when it is injected underpressure into the nucleus pulposus of the disk.

[0007] Typically any syringe with a mechanism for measuring pressure hasbeen used to measure the patency of the inter-vertebral disk. However,such syringes typically utilize a transducer mounted at the distal endof the syringe barrel which is in communication with the fluid path ofthe syringe. The presence of a non-transparent transducer and associatedfixtures adjacent the fluid path prevents clear vision of bubbles in thecontrast media or other imperfections that may be of concern ininterventional procedures. Such devices are described in U.S. Pat. Nos.5,021,046 and 5,084,060. Also, many such devices are awkward to use, areunduly complex or fail to provide a flexible fluid pressure adjustment.

BRIEF SUMMARY OF THE INVENTION

[0008] The instant invention involves a hand-operated syringe forapplying pressure to a fluid within the syringe which pressurized fluidinteracts, directly or indirectly, with some physiology of the humanbody. The syringe has a barrel, preferably constructed of a transparentrigid material. A plunger adapted to slide within the barrel and toapply pressure to fluid within the barrel is constructed to have twooperative motions: 1) a first sliding motion induced by direct handmotion, e.g., thumb force, at the proximal end of the plunger or someplunger extension attached generally axially to the proximal end of theplunger whereby a rapid increase or decrease in the fluid pressure canbe controllably caused to occur within the syringe barrel and 2) asecond motion wherein the plunger is not freely slidable but has threadswhich interact with an adjustment mechanism wherein the adjustmentmechanism is engageable and disengageable to permit minute axial motionof the plunger to be made and thus adjust the applied fluid pressure incontrolled micro pressure adjustments.

[0009] The adjustment mechanism includes means whereby the threads onthe plunger may be rapidly (instantaneously) disengaged to permit theplunger to slide freely thereby instantaneously releasing the fluidpressure within the syringe barrel. The adjustment mechanism engagesthreads on the plunger or on a casing (sleeve) associated with andenveloping at least a portion of the plunger's external surface.

[0010] A further feature of the syringe is a pressure monitoring systemwhereby the pressure of the fluid within the barrel may be observed and,by appropriate adjustment of the plunger, such pressure controllablyincreased, decreased or released.

[0011] Since it is desired generally to monitor applied fluid pressure,a pressure sensitive transducer is fitted to communicate directly, orindirectly, with the fluid within the syringe barrel. Such transducershave conventionally been attached to the barrel generally at or near thedistal end of the barrel as illustrated in U.S. Pat. Nos. 5,021,046;5,009,662 and 5,004,472 to Wallace. While such positioning of thepressure sensitive transducer is acceptable for many purposes, thetransducer and its associated fittings are not transparent and block thevision of a syringe operator of the fluid within that portion of thebarrel adjacent the transducer. This may often be very disadvantageousif air bubbles exist within the fluid within the syringe barrel orwithin the tubing leading to a patient's body especially where the fluidis intended to enter a portion of the body such as occurs with fluidinjection into a spinal disk.

[0012] A significant advantage is realized by attaching the transducerto the distal end (pressure tip) of the plunger and having at least apart of the electronics which are part of the pressure-monitoringapparatus contained within the body of the plunger. Such a transducerand electronics arrangement is especially useful inasmuch as theelectronics may emit a wireless signal to cause a pressure reading tooccur on a remote display, i.e., a display located on the exterior ofthe syringe barrel or a remote display not attached to the syringebarrel, including a display positioned at or near the proximal end ofthe syringe plunger or an extension attached thereto.

[0013] One very advantageous arrangement is to have all the necessaryelectronics to be contained within the syringe plunger and have adisplay incorporated in the plunger and positioned at or near theproximal end of the plunger. The display is thus within the vision fieldof a syringe operator who is focused on the syringe fluid. The displaymay interact with the electronics associated with the pressuretransduced by an electrical conductor or by wireless means.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0014]FIG. 1 is a perspective view of a syringe of the instantinvention;

[0015]FIG. 2 is a perspective view of the proximal portion of thesyringe of FIG. 1;

[0016]FIG. 3 is an exploded view of a syringe plunger and encasingsleeve;

[0017]FIGS. 4 and 5 are exploded views of components associated with theplunger tip;

[0018]FIGS. 6A-6C include several views of a clamshell locking mechanismfor a syringe of the instant invention;

[0019]FIG. 7 is a cross-sectional perspective view of the syringe ofFIG. 1;

[0020]FIGS. 8A-8C are perspective views of a syringe with a streamlinedblock-shaped head containing the pressure display;

[0021]FIG. 9 is a cross-sectional view of a plunger having electronicmeans which transmits a wireless signal to a pressure display located atthe proximal end of the plunger; and

[0022]FIG. 10 is a perspective view of the syringe of FIGS. 8A-8C withfanciful display holder.

DETAILED DESCRIPTION OF THE INVENTION

[0023]FIG. 1 is an external perspective view of a syringe 10 of theinstant invention having the electronics housed in the plunger 11, athumb ring 12 affixed to the proximal end of the plunger for control offluid pressure syringe. The plunger is enveloped at least partially by arotatable sleeve 16 with a captivated thread mechanism 13 capable ofrotating independent of the plunger end cap 19, and a sliding lockmechanism 17 and 18. The syringe barrel 14 is similar to one known inthe art and incorporates rings 15 and 15 a for the index finger and themiddle finger. The triangular arrangement of the plunger thumb ring 12and barrel rings 15 and 15 a facilitates one-handed operation of thesyringe. This is a great advantage for any physician or technicianperforming any procedure in which fluid pressure is directly orindirectly applied to any human body part including a spinal disk or anartery. It is typically advantageous to have one free hand foraccomplishing other tasks during any operation of the syringe.

[0024] The syringe barrel has a luer lock or a slip socket 20 for abonded extension line. The locking mechanism housing 17 is molded toattach to the proximal end of the syringe and captivates a slidingthread locking mechanism 18 that engages or releases the threads ofsleeve 16. Sliding this mechanism to one side allows the plunger totravel free in the barrel, sliding to the other side locks the mechanismand requires that the thumbwheel 23 be rotated to generate minutemovement of the plunger and associated volume or pressure change in thesyringe lumen.

[0025] As illustrated in FIG. 2, the cutout 25 in the body of the slidelock 18 is a keyhole-shaped opening with a minor width such that it willengage with the threads of the threaded sleeve 16 (see FIG. 3), and hassufficient relief in its major diameter to allow free travel of thesyringe plunger when threads of the sleeve are disengaged. Rapiddisengagement is very desirable since many procedures may require aninstantaneous release of fluid pressure to prevent or minimize somedamage to a body part being treated or investigated.

[0026] The plunger of the syringe illustrated in FIG. 3 has a smoothinner bore 26 and outer bore 27. The outer bore 27 becomes thesupporting surface for the rotation of the threaded sleeve 16. When thelocking slide 18 is engaged with the threads of the threaded sleeve,displacement of the plunger is generated by rotation of the thumbwheel23 which forces the distal end of the sleeve 16 against a flange, suchas provided by plunger end cap 19 adjacent the distal end of theplunger. The axial advancement or retraction of the plunger effected byrotation of thumbwheel 23 is very slight, thus minute adjustments offluid pressure are readily accomplished. Also advantageous is thelocation of the thumbwheel 23 since its position vis-a-vis rings 15 and15 a and thumb ring 12 readily permits an operator's thumb to be removedfrom thumb ring 12 and placed upon thumbwheel 23 to rotate thumbwheel 23to achieve minute fluid pressure adjustments. This continuous one-handedoperation of the syringe is very advantageous for a variety of reasons.

[0027] The plunger end cap 19 receives an electronic transducer, similarto those described and illustrated in the U.S. patents to Wallace, citedhereinabove, which is retained by the transducer retainer 31. Thefriction reduction washer 30 is placed on the plunger's smooth outerbore 27 after the threaded sleeve 16 is slid over plunger 11, it acts asa friction reducing bearing between the threaded sleeve and the plungerend cap 19. The rubber plunger tip 32 is snapped over the detent 33 ofthe plunger end cap 19.

[0028] The plunger tip assembly consists of a transducer that seats intothe plunger end cap 19. The cavity of the plunger end cap 19 is filledwith a force transmitting silicone gel which allows the transmission offorces to the transducer. Other arrangements for appropriate attachmentof the transducer to the plunger tip may, of course, be utilized.

[0029] While a slide-lock mechanism has been illustrated and describedherein, other locking mechanisms may be effectively utilized. Forexample, a two-piece clam-shell, spring-loaded mechanism such as thatshown in FIG. 6 can be usefully employed. A pair of clam-shaped elements34 and 35 are hinged at their closed end and spring-biased to be in aclosed position whereby they clamp the treaded sleeve or a threadedplunger. A rotatable cam 36 is positioned at the open end of theclam-shaped elements whereby rotation of the cam 36 forces theclam-shaped elements into an “open” position whereby a threaded sleeveor plunger may slide freely between them. The “closed” position isillustrated in FIG. 6A while FIGS. 6B and 6C illustrate the closedposition. The transducer may also be utilized in a conventional manner,as illustrated in U.S. Pat. No. 5,004,472 to Wallace.

[0030] Other mechanisms of locking a threaded sleeve or plunger in afixed position or to provide minute pressure adjustment may be employed,including locking mechanisms disclosed in prior patents, such as U.S.Pat. Nos. 5,860,955; 5,433,707 and 5,685,848.

[0031] Preferred locking mechanisms are those which are operable by thesame hand which is otherwise holding or operating the syringe.Preferably, the locking mechanism can be set or released by the thumb ofthe hand engaging one or more of the finger rings of the syringe.

[0032] As stated hereinabove, having a threaded sleeve engage thelocking mechanism permits minor axial adjustments of the plunger withoutrotation of the plunger itself which keeps a pressure readout display 39affixed at the proximal end of the plunger in a continuously visibleposition. However, if the pressure transducer and associated electronicsare all incorporated as part of the plunger and the electronics send awireless signal to a remote display, then the plunger itself may betreaded near its proximal end for engagement with a suitable lockingmechanism to accomplish minute axial adjustment of the plunger which iscaused by minor rotation of the plunger. A thumb ring for a threadplunger with a slightly larger open diameter may facilitate positioningof an operator's thumb even though the thumb ring may be rotatedslightly. Also, a thumb ring which is fixed to a threaded plunger so thethumb ring freely rotates also accommodates plunger rotation.

[0033] Thus, a plunger which incorporates pressure transducer andassociated electronics is useful with either a threaded plunger or athreaded sleeve freely encasing the plunger.

[0034]FIG. 7 is a perspective, sectional view along a longitudinal planeencompassing the central longitudinal axis. The finger rings 15 and 15 aand thumb ring 12 are shown at the proximal end of the syringe. The opencentral cavity 37 of the plunger is exposed. It is in this space that anelectronics assembly may be incorporated to connect a pressuretransducer in the plunger top to a pressure read-out display located inthe display holder 11 located at the proximal end of the plunger.

[0035] The plunger 11 and its threaded enveloping sleeve 16 areillustrated in an inserted position in the syringe barrel.

[0036] The thumb wheel 14 and slide lock are also illustrated. Thesleeve and plunger slide longitudinally within the syringe barrel exceptwhen the slide lock engages the threads of the sleeve. The thumb wheelis fixed to the sleeve so that rotation of the thumb wheel rotates thesleeve threads with respect to the slide lock causing the plunger toadvance or withdraw depending upon the direction of rotation of thethumb wheel.

[0037] Rotation of the thumb wheel while the slide lock engages thethreads of the sleeve causes minute longitudinal movement of the plungerpermitting minor adjustments in the fluid pressure in the barrel andattached lumen. Such precise adjustment of fluid pressure is verydesirable for a number of medical procedures, such as discography andangioplasty procedures.

[0038] Fluid pressure within the barrel may be quickly decreased to zeroby unlocking the slide lock and allowing the plunger to retreat.

[0039] A further embodiment of the invention incorporates a wirelesstransmission of pressure information from the pressure transducer to theread-out display at the proximal end of the syringe. The transduceranalog output may be introduced to a wireless transmitter to transmit ananalog signal to the distal end of the syringe where a wireless receiverreceives said signal, converts it to a digital signal which isintroduced directly into the digital read-out display.

[0040] The wireless transmitter may be an infra-redprocessor/transmitter which receives the analog electrical signal,converts it into an infra-red analog signal which is emitted from an IRemitter. The IR analog signal is transmitted through the body of thesyringe preferably through an open channel to an IR analogreceiver/converter at the proximal end of the syringe. Alternatively,the electrical signal may be converted into a digital IR or otherdigital wireless signal to be received by an appropriate receiver. Anoptical fiber may be advantageously used for precise IR transmissionfrom the IR transmitter to the IR receiver. Further, a digital signalmay be sent via an electrical conductor between thetransducer/transmitter and the receiver/display.

[0041] The disclosure of U.S. Pat. Nos. 5,215,523 and 5,387,194 toWilliams/Call et al. are incorporated herein by reference, especiallywith respect to means and systems for wireless transmission of signalsproduced by a pressure transducer. Also, incorporated herein is U.S.Pat. No. 5,021,046 to Wallace, especially the disclosure relating topressure transducers.

[0042] Also, wireless transmission of pressure transducer information byradio signals may be utilized within the syringe for the purposes of theinvention. However, radio signals may interfere with various otherequipment in an operating room-type of environment and would generallybe contraindicated where such a syringe was to be utilized upon apatient having a pacemaker.

[0043]FIGS. 8A-8C are perspective views of a syringe with a pressuredisplay head located in a display holder having a thumb aperaturelocated between the display and the plunger.

[0044]FIG. 8A is a perspective view of a syringe with a pressure displayhead located in a display holder having a thumb aperature locatedbetween the display and the plunger. This particular syringe mayincorporate the wired connection between the pressure transducer and thepressure display or a wireless transmission system such as thatillustrated in FIG. 9.

[0045]FIGS. 8B and 8C show an elevational view and plan view,respectively, of the syringe (infuser) of FIG. 8A. The display holdingportion 37 of the syringe is unique in appearance, as can be seen inFIGS. 8A, 8B and 8C. Additionally, the style, shape and juxtaposition ofthe various elements of the syringe provide further a syringe of adistinctive appearance.

[0046]FIG. 8C shows the bottom of the display holder, assuming that thesurface in which the display is embedded, is denoted the top surface,which is visible in FIGS. 8A and 8B.

[0047] The syringe of FIGS. 8A, 8B and 8C has the thumb preferablyinserted in thumb aperature 38 from the bottom so that the display 39will face upwards to the technician operating the syringe.

[0048] This particular syringe may incorporate the wired connectionbetween the pressure transducer and the pressure display or a wirelesstransmission system such as that illustrated in FIG. 9

[0049] An embodiment of the invention is shown in FIG. 9 illustrating inperspective view a hollow plunger 11 having a pressure sensingtransducer 38 located at or near the plunger tip 39 (distal end), whichtransducer is electrically connected to an electronics system 40 whichwirelessly transmits its output signal (IR or RF) to a remotereceiver/pressure display 41 system. The display 42 may be located at ornear the proximal end of said plunger or at a remote location separatefrom said plunger, e.g., attached to an external surface of said syringeor entirely separate and remote from said syringe, e.g., on a supportwhich positions said pressure display visible to one or more members ofa team involved in an infusion procedure.

[0050] The signal transmitted from said electronics system to saiddisplay may be an analog or digital signal. If the signal is an analogsignal then the pressure display includes a receiver mechanism whichreceives said signal and converts the analog signal to a digital signalsuitable for being displayed as a pressure in millimeters of mercury,pounds per square inch or other useful pressure units. The displaymechanism may further have a memory device whereby the total infusionprocedure is recorded in terms of elapsed time and regular(substantially continuously, if desired) pressure recordings so that ahistory of the entire infusion procedure may be later downloaded forpermanent storage.

[0051] A substantially hollow plunger having an internal pressuresensing mechanism, e.g., pressure transducer, in the tip which is indirect or indirect contact with fluid of a syringe being pressurized hasmany advantages, many of which have been enumerated herein. One suchadvantage is that a direct pressure reading may be displayed in adisplay incorporated in the proximal end of the plunger. Also, in astructure such as described herein, a fluid, preferably liquid, may becontained within the hollow plunger to contact a dynamic (diaphragm)type-pressure influenced mechanism and conduct the received pressurethrough said fluid, preferably liquid, to a pressure transducer/displayin the proximal end of said plunger.

[0052] In such a structure the pressure experienced at the tip of theplunger is transmitted by a fluid conductor to a pressure transducer orother pressure metering means, e.g., an analog pressure meter, at theproximal end of the plunger. Such a structure permits all theelectronics necessary for a digital display, e.g., pressure transducer,analog/digital converter and digital signal receiving display to bedirectly coupled to one another and located at or near the proximal endof the hollow plunger.

[0053] The display at the proximal end of the syringe may beincorporated into a housing of the varying shapes and designs shownherein which accommodate functional purposes. The shape of the displayhousing shown in FIGS. 8A-8C is particularly fanciful to provide asmooth aesthetic appearance while not diminishing its attributes as adisplay holder and thumb engagement device. A further perspective viewof the syringe of FIGS. 8A-8C is shown in FIG. 10. The view is at anoblique angle from the rear of the syringe.

[0054] The above description is to aid in understanding the invention;the full scope of which is set forth in the appended claims.

What is claimed is:
 1. A pressure applying and monitoring syringe havinga barrel and an internal plunger in which a pressure transducer isincorporated into said plunger.
 2. The syringe of claim 1, in whichpressure sensing electronics associated with said pressure transducerare incorporated as an integral part of the plunger.
 3. An improvedcatheter syringe comprising: a hollow barrel; a piston (plunger) adaptedand structured to slide within said barrel; and pressure sensing meansfitted to the distal end of said plunger, said pressure sensing meansadapted and structured to sense fluid pressure within said barrel and togenerate an electronic signal proportional to said pressure.
 4. Theimproved catheter syringe of claim 3, wherein said pressure sensingmeans is connected electrically to electronic signal processing meanslocated within said plunger.
 5. The improved catheter syringe of claim3, wherein said plunger has a pressure display attached to the proximalend of said plunger which extends outside the proximal end of saidbarrel.
 6. An improved catheter syringe comprising: a barrel; a plunger;dual plunger advancement means wherein: a first means is structured andadapted to interact with said barrel and said plunger to provide rapidplunger advancement, and a second adjustment means structured andadapted to provide slow, precise plunger advancement; and wherein saidplunger advancement means includes a quick-release mechanism to allowsaid plunger to slide freely within said barrel in order to rapidlyrelease fluid pressure within said barrel.
 7. The fluid pressureinducing syringe of claim 6 further comprising: a transparent barrel; aplunger (piston) having a pressure sensing transducer affixed to theplunger adjacent the tip (distal end) of the plunger wherein saidtransducer emits an electrical signal proportional to the magnitude ofthe sensed pressure; electronics components to convert said electricalsignal received from said transducer to communicate said electricalsignal to a display for displaying a pressure reading.
 8. A fluidpressure inducing syringe comprising: a barrel; a plunger; a sleeve witha threaded portion encompassing at least a portion of said plunger, saidsleeve freely rotatable about the plunger; locking means associated withsaid barrel whereby said locking mechanism engages the threaded portionof said sleeve to lock the sleeve and plunger in an axially immobileposition.
 9. The syringe of claim 8, wherein said sleeve and lockingmechanism have cooperative means adapted and structured to permitrotation movement of said sleeve with respect to said locking mechanismto cause minute axial motion of said sleeve and plunger.
 10. The syringeof claim 9, wherein said cooperative means is adapted and structured toaccommodate to an operator's phalanges actuation to engage said lockingmechanism and to rotate said sleeve.
 11. A fluid pressure inducingsyringe comprising: a barrel; a plunger; a pressure sensing transducerpositioned to sense fluid pressure within said barrel; a pressuredisplay affixed as part of the proximal portion of said plunger saiddisplay receiving electrical signals directly or indirectly from saidpressure transducer.
 12. The syringe of claim 11, wherein saidelectrical signals from said pressure transducer are transmittedwirelessly to said pressure display.
 13. The syringe of claim 11,wherein said electrical signals are received by said display through anIR receiver which receives IR signals from an IR transmitterelectrically connected to said transducer.
 14. The syringe of claim 12,wherein said electrical signals are transmitted wirelessly to a pressuredisplay remote from said syringe.
 15. The syringe of claim 11, whereinsaid plunger is hollow and contains a fluid which is positioned betweena pressure influenced diaphragm at the plunger distal end and a pressuretransducer located between said plunger and remote from said distal endof said plunger.
 16. A fluid pressure inducing syringe comprising: abarrel; a hollow plunger having a pressure influenced diaphragm at itsdistal end; a fluid within the hollow plunger communicating the amountof pressure realized at the distal end of the plunger to pressurereadout means proximate the proximal end of said plunger.